You can simply stop HAD first on that node. (cluster service)
hastop -local -force
Then you will be able to delete the RDS/RVG as cluster is not monitoring it anymore.
But..... Because you are permanently deleting it from your environment it seems, you should delete the relevant RVG resource/s from the cluster first. (via java gui willd do)
This way, you wouldn't even need to stop the HAD as you have made the cluster not monitor that RVG anymore. (Hence VEA won't compain once resource is deleted)